At least 13 soldiers and 13 suspected al-Qaeda members died in an attack on an army base in Yemen’s southern province of Abyan on Friday, medical and military sources said.

Violence has intensified in Yemen in recent weeks. The United States, wary of the growing power of al-Qaeda, has stepped up drone strikes on suspected militant positions and militants have increased attacks on state and army targets.

Two militants wearing army uniforms drove an explosives-laden car into the military base, killing themselves and 10 soldiers and injuring 15 other soldiers, a military official said.

Moments later, a group of militants attacked the base from the sea and 11 more militants and three soldiers were killed in the fighting that followed.

“The two suicide bombers were wearing army uniforms, and even their car had a military numberplate, so they didn’t raise any suspicion,” an injured soldier told reporters by telephone from hospital.

On Thursday, nine suspected al-Qaeda militants were killed in what a security source and residents said was a US drone attack on a farmhouse outside a town in southern Yemen that was held by militants last year.

Yemen’s wealthier Gulf neighbours and Washington are concerned that al-Qaeda and other Islamist militants operating in Yemen could pose a threat to top oil producer Saudi Arabia and to nearby shipping lanes.

The Yemen-based al-Qaeda in the Arabian Peninsula and other militant groups strengthened their grip on parts of the country during an uprising that ousted veteran President Ali Abdullah Saleh in February.